Septic Thrombophlebitis: An Imaging Review

Septic thrombophlebitis, infected thrombus within a vein, accompanies primary infections and can lead to abscesses and septic emboli. Imaging modalities such as ultrasound, CT, and MRI can identify venous filling defects, vein wall thickening, and surrounding inflammation with fluid and fat stranding, findings that suggest septic thrombophlebitis even if the underlying infection is not visible. Septic thrombophlebitis can occur in many different veins, although some locations are more commonly affected. Lemierre syndrome involves the internal jugular vein after pharyngitis and often leads to septic pulmonary emboli. Pylephlebitis involves the portal and mesenteric venous system and is commonly associated with intraabdominal infections such as diverticulitis and necrotizing pancreatitis. Pelvic septic thrombophlebitis typically occurs postpartum or after surgery and includes ovarian vein thrombosis and deep septic pelvic vein thrombosis. Imaging is key to the diagnosis of septic thrombophlebitis, allowing timely initiation of treatment and reducing associated morbidity and mortality. This Pictorial Essay reviews the multimodality imaging appearance of septic thrombophlebitis with an emphasis on common locations and presentations.